<head>
  <style> body { margin: 0; } </style>

  <script src="//unpkg.com/force-graph"></script>
  <!--<script src="../../dist/force-graph.js"></script>-->
</head>

<body>
  <div id="graph"></div>

  <script>
    // Random tree
    const N = 20;
    const gData = {
      nodes: [...Array(N).keys()].map(i => ({ id: i })),
      links: [...Array(N).keys()]
        .filter(id => id)
        .map(id => ({
          source: id,
          target: Math.round(Math.random() * (id-1))
        }))
    };

    // gen a number persistent color from around the palette
    const getColor = n => '#' + ((n * 1234567) % Math.pow(2, 24)).toString(16).padStart(6, '0');

    const Graph = new ForceGraph(document.getElementById('graph'))
        .nodeCanvasObject((node, ctx) => nodePaint(node, getColor(node.id), ctx))
        .nodePointerAreaPaint(nodePaint)
        .nodeLabel('id')
        .graphData(gData);

    function nodePaint({ id, x, y }, color, ctx) {
      ctx.fillStyle = color;
      [
        () => { ctx.fillRect(x - 6, y - 4, 12, 8); }, // rectangle
        () => { ctx.beginPath(); ctx.moveTo(x, y - 5); ctx.lineTo(x - 5, y + 5); ctx.lineTo(x + 5, y + 5); ctx.fill(); }, // triangle
        () => { ctx.beginPath(); ctx.arc(x, y, 5, 0, 2 * Math.PI, false); ctx.fill(); }, // circle
        () => { ctx.font = '10px Sans-Serif'; ctx.textAlign = 'center'; ctx.textBaseline = 'middle'; ctx.fillText('Text', x, y); } // text
      ][id%4]();
    }
  </script>
</body>